System of radio telegraphy and telephony



J. HAMMOND, 1R. 'SYSTEM OF RADIO TELEGRAPHY AND TELEPHONY.

4 APPLICATION FILED JUNE l5. 19l2- RENEWED FEB- 5,1919. 1,372,425.

Patented Mar. 22, 1921 ATTORNEYS ,umreo STATES PATENT orrrce.

JOHN HAYS HAMMOND, an, or etcocnsrnn, mnssncnusnrrs.

SYSTEM OF RADIO TELEGBAPHY-AND TELEP Application filed June 15, 1912, Serial No. 703,836. Renewed February 5, 1919. Serial No.

To all whom it may concern:

Be it known that I, JOHN HAYS IIAM- MOND,.JI., a citizen of the United States,

without interfering with each other, and the.

simultaneous transmission and reception of a plurality of messages at each station.

The principal feature of the invention is a system of synchronously rotating interrupters which alternately connect transmitters and receivers to the antenna in such a manner that the receiver is inoperative when the transmitter is operative, and vice-versa.

. When the entire apparatus is at one station for use with one antenna, the 'interrupters are mechanically connected so as to rotate synchronously. If two nearby stations are operated on this system, the motors for the interrupters are electrically connected, in any manner Well known in the art, to obtain synchronous rotation. In this case the two stations would transmit simultaneously and receive simultaneously, with respect to each other. That is, at each station the antenna would be connected to the transmitter and the receivers would be disconnected at the same instant, so that neither station could re ceive during the instant that either transmitter would be connected for operation.

If the interrupters be revolved at a speed which will produce an ultra-audible interrupting rate, each station can transmit and receive simultaneously without mutual interference. In addition to this freedom from mutual interference my system possesses a very high degree of selectivity, since the re ceivers are tuned to a plurality of predetermined characteristics of the transmitted wave signals.

However, any speed of the interrupter or commutator may be. used that is suitable, and synchronism of the rotating interrupters or commutators may be attained by either wire or either wave connection between the different stations.

Specification of Letters Patent.

coil L ferent from that of alternator H.

Patented Mar. 22, 192i.

Referring to the drawings Figure 1 represents a radio telegraph and telephone station on my system.

Fig. 2 represents a similar radio telegraph and telephone station in the station shown in Fig. 1.

In Fig. 1, H a high-frequency alternator or other oscillatory current generator connected through coupling coils L and L With antenna A. In circuit with antenna A are an interrupter I, coil L, and either a telephone transmitter T, or an interrupter I and a key K, according to the position of the switch S. This antenna circuit is grounded at E. The interrupter I has a frequency above the limits of audibility, and the interrupter I has a frequency within the limits of audibility. The above described apparatus constitutes the transmitting side of the station.

A lso connected to antenna A. is an open rcceiv ng clrcuitcomprising an interrupter I a co1l L and a variable condenser C. This clrcult is also grounded at E. The interrupters I and I are both mechanically con nected to the motor M, and are both operated at a rate above the limits of audibility, in such a manner that they are not in contact at the same time, but so that when vicinity of the one makes connection, the other is out of connection. Coupled to the receiving antenna circuit by means of the coils L and If is the closed oscillatory circuit composed of inductance coil L and variable condenser C ,'which closed oscillatory circuit, bv the action of rectifier It, supplies energy to receiving telephone P, and also, through coupling coils L and L to a circuit having a lower frequency, composed of inductance condenser C and receiving telephone P The telephone P is used to receive telephone messages, and the telephone P is used to receive telegraph signals.

In Fig. 2 is shown a station :similar to that in Fig. 1. H is a high frcquency alternator, whose frequency is preferably dif- H is inductively connected with transmitting antenna circuit A I L S W, which also in cludes either telephone transmitter T- or interrupter I and key K according to the position bf switch S The antenna is also connected with the receiving circuit I If G which is also grounded at E. This receiv I ing circuit is inductivelIy operate synchronously, and in cases where both the stations shown in Figs. 1 and 2 are combined in one station, the motors M and M may be connected mechanically.

Antenna cif'cuits A L C E and A L C E and closed oscillatory circuits L C and L" C are tuned to high frequencies, such as are suitable for electric wave transmission, and circuits L C P and L C P are tuned to frequencies within the limits of audibility, so as to receive telegraph signals from distant stations. These circuits of each station are in resonance with the electric wave characteristics of distant transmitting stations with which they are respecwithout interfering with each other.

tively in operative communication, and the characteristics of the transmitted electric waves from each station shown in Figs. 1 and 2 are in resonance with the receiving circuits of the respective distant stations with whichthey are in operative communication. The corresponding circuits'of the stations in Figs. 1 and 2, however, shouldv not be in tune with each other, as these stations are not intended for radio communication with each other, but are designed to be in communication with distant stations,

Various changes and modifications, within the skill of those versed in the art, may

. be made inthe particular apparatus shown and described herein, without departin from the spirit of my invention, provided I the means set forth in the following claims be employed.

Iclaim as my invention:

1. In a system of radio telegrapl'iy and telephony, a plurality. ot',stations, trans mitting. and receiving apparatus at each of said stations, said stations being operatively connected to transmit at the same time and to receive at the same time, and automatic means operatively connected with said transmitting and receiving apparatus to cause said-stations to transmit simultaneously and to receive simultaneously.

2. In a s stem of radio telegraphy and telephony, means for transmitting and receiving at a plurality of stations, including interrupter-s alternately" connecting the antennee 'with the receiving and the sending apparatus, so that the receiving apparatus at all the stations are connected sym-hronously and the sending apparatus at all the stat ions are Connected syiuzhronously. said interrupters being operated at a rate above the limits of audibility without breaking the operating continuity.

3. In a system of radio telegraphy and telephony, a plurality of sending and a plurality of receiving sets of apparatus. and means for interrupting all the sets of sending apparatus synchronously and all the sets of receiving apparatus synchronouslyand for interrupting the sending apparatus and the receiving apparatus alternately at a rate .above the limits of audibility.

4. A method of radio telegraphy and lelephony which consists in causing a plurality of stations to cooperate automatically in such a manner as to transmit simultaneously and to receive simultaneously, and in cansing each of said stations to transmit and to receive alternately.

5. A method of radio telcgraphy and lelephony which consists in causing a plurality of stations to cooperate automatically in such a manner as to transmit syiu-hronously and to receive synchronously, and in causing each of said stations to transmit and receive alternately at a 'rate above the limits of andibility.

6. In a system of radio telegraphy and telephony, a plurality of stations, each compris ng transmitting apparatus and receiving apparatus, means for operativcly connect ing said stations synchrontmsly. and means for causing all ofsaid transmitting apparatus to operate alternately with all of said receiving apparatus.

In a system of radio telegraphy and telephony, a plurality of st tions, means operatively connecting the stations for causing them to transmit simultaneously and to receive simultaneously, and means for causing said stations to transmit and receive alternately.

8. In a system of radio telegraphy and telephony, a plurality of stations, means for causing said stations to transmit and receive electric waves having a plurality of characteristies, and means operatively connecting said stations for causing said stations to transmit electric waves simultaneously and to receive electric waves simultaneously and to transmit and receive electric waves alternately.

9. In a system of telegraphy and telephony, the combination with a source of electrical oscillations, of means. operative either to interrupt said oscillations at the will of an operator, or to impress irregular undulations corresponding to sound waves upon said oscillations, means for receiving either interrupted electrical oscillations or said electrical oscillations having irregular undulations corresponding to sound waver impressed thereon, and means operatively connecting said first mentioned means and said second mentioned means, and automati cally operative to cause said first mentioned 'means to become operative alternately With said second mentioned means.

10. In a system of telegraphy and telephony, the combination With'a source of electrical oscillations, of means operative either to interrupt said oscillations at the will of an operator, or to impress irregular undulations corresponding to sound Waves upon said oscillations, means for receiving either interrupted electrical oscillations or electrical oscillations having irregular undulations corresponding to sound Waves impressed thereon, and means operatlvely connecting said first mentioned means and said of alteration above the limits of audibility.

This specification si ned and *Witnessed this 22nd day of May, D., 1912.

JOHN HAYS HAMMQNQJR.

Signed in the presence of:

MABEL J. COOPER, OLIVE B. KING. 

